Reactive arthritis: update 2018.

At this time, reactive arthritis (ReA) is considered to be part of the spectrum of the spondyloarthritis, previously known as Reiter's syndrome, and refers to an infection induced systemic illness, characterized by a sterile synovitis occurring in a genetically predisposed individual, secondary to an infection localized in a distant organ/system, but also accompanied with multiple extra articular manifestations.